Stroke is a major complication that causes disability or death of patients suffering from atrial fibrillation (AF). As indicated by epidemiological data, about 15 million people worldwide suffer from stroke each year, and 15% to 20% of the strokes are caused by atrial fibrillation. Study suggests that, cardiogenic thrombus of 60% of patients suffering from rheumatic heart disease with atrial fibrillation is from left atrial appendage, and this proportion is larger than 90% in patients suffering from non-valvular heart disease with atrial fibrillation. Therefore, the study of thromboembolic complications of atrial fibrillation has received more and more attention, and prevention and treatment of stroke in patients with atrial fibrillation have great clinical significance.
At present, there are three methods for treating atrial fibrillation, which include surgery, medication and internal medicine intervention. The left atrial appendage is the key to the treatment of atrial fibrillation due to its important role in the thrombosis formation of patients with atrial fibrillation. In the early, surgery is performed to occlude the left atrial appendage, however, this method has disadvantages of large trauma and high risk, thus has not been widely used clinically. Although the effect of preventing the stroke in patients with atrial fibrillation by using anticoagulants has been well received, some patients, particularly elderly patients who have a high incidence of atrial fibrillation, can not benefit from the anticoagulant therapy because of bleeding tendency or contraindications to anticoagulant therapy such as bleeding. At present, the most advanced treatment for preventing thromboembolic complications of atrial fibrillation domestic and overseas is percutaneous left atrial appendage occlusion, which releases a specialized occluder through a catheter to occlude the left atrial appendage, so as to prevent atrial fibrillation fundamentally. This kind of minimal invasive intervention treatment has benefits of short duration, small trauma and more effective, especially for those patients who have contraindications or a high risk of bleeding if taking anticoagulants.
There are considerable limitations in conventional percutaneous left atrial appendage occlusion in which an occluder is positioned into the left atrial appendage by means of catheter intervention. Most of occluders cannot fully fit the anatomic structure of the left atrial appendage because of the left atrial appendage has a complicated anatomic structure and various shapes and depths, thus the occluder is difficult to be stably fixed. The opening and the interior of the left atrial appendage has irregular shape and uneven surface, thus the coating of the occluder may form a number of concave pit-shaped gaps at the opening of the left atrial appendage, and cannot completely occlude the opening of the left atrial appendage, thus the desirable occlusion effect cannot be achieved. Also, in conventional products, a soft anchoring thorn is difficult to stab into the wall of the left atrial appendage, thus cannot be stably fixed, and a hard anchoring thorn has an enough puncture force, but may hinder the recovery, relocation and replacement of the occluder, and may even pierce the left atrial appendage. In addition, since the occluder is located within the left atrial appendage, its support force may expand the left atrial appendage, which may lead to abrasion between the left atrial appendage and the pericardium.